Learning from a recent incident

1. Learning from a recent incident • This presentation consist of 6 view graphs (plus this header) • Action required: • To be distributed to relevant staff and to be discussed HSE meetings in the context of your own operations • To verify that you have a control system in place to prevent incidents from hydrocarbon leaks

2. The incident: A Natural Gas Condensate leak in one of the legs of an offshore production platform resulted in exposure to hydrocarbon vapours, causing the death of two operators Background: The narcotic hazard of natural gas condensate had been identified in the Health Hazard Register and the Material Safety Data Sheet (MSDS) The HEMP analysis had identified leaks as an exposure threat, but indicated that normal plant integrity procedures should identify and control/repair leaks when they occur The HRA process and Leg Entry Procedures had identified the required control measures and emergency procedures Nevertheless, it appears that the hazard was poorly understood in the line and appropriate procedures and control measures were not implemented

3. The hazards: The narcotic effect of a hydrocarbon mixture depends on the dose and the concentrations of the various hydrocarbons in the mixture Narcotic effects occur very quickly – within 2-3 breaths. This can result in confusion and inability to take rational decisions, and finally to unconsciousness and death Narcotic effects from hydrocarbon vapours can occur at normal oxygen concentration in air, so the oxygen depletion alarm does not protect from narcotic effects Alarm levels of portable and fixed monitors are set as a percentage of the Lower Explosion Limit (LEL) – alarm should trigger appropriate action, i.e. respiratory protection and immediate evacuation

4. 100% 80% 60% 40% 20% Narcotic Effect vs Portable Monitor Reading Corresponds to approx 50% general anaesthetic dose required for surgical operations Failure to respond to verbal commands Hyper-excitation, loss of ability to take rational decisions % Lower Flammable Limit No Impairment of Functionality Alarm setting for monitor This is an example. Actual effects depend on the nature of the hydrocarbon vapour

5. Learning and Actions – Toxic Substances in Confined Spaces Leaks of toxic substances in confined spaces can quickly result in hazardous concentrations in breathing air As well as direct health risks, these can result in confusion and inability to react properly Competence Assurance Systems should verify that the appropriate personnel and supervisors are fully familiar with the understanding of the hazards of toxic substances and confined space entry procedures Substances heavier than air, such as butane, can collect in low points, resulting in toxic or flammable pools which may not be detected by fixed gas heads or portable monitors as normally positioned Further guidance is provided in the Group Guide Confined Space Entry,which be issued in April 2004

6. Learning and Actions – HEMP for Confined Spaces The Hazard and Effects Management Process (HEMP) should be applied for confined space activities The HEMP should contain the following – Identification of the hazards Assessment of the risks using the Risk Assessment Matrix (RAM) Analysis of the hazards, e.g. by Job Hazard Analysis (JHA) and HRA as indicated by the RAM Necessary controls and recovery measures Demonstration that controls and recovery measures are effective The HEMP should demonstrate that alternatives to entering the confined space have been considered, and all reasonably practicable steps taken to eliminate hazards to health Confined space entry should be authorised and controlled by Permit to Work

7. Learning and Actions – HEMP for Confined Spaces The HEMP and JHA should also cover hazards which may be released into the confined space for reasons not directly connected with the activity, for example a leak from pipework Findings of the HEMP and HRA should be incorporated into operating procedures, tool-box talks, training etc. Cross-checks should be made against the HRA to ensure all health risks are being managed The HEMP, JHA and HRA should clearly specify the monitoring and escape procedures to be adopted. This should include the monitoring devices to be used, alarm levels, and escape and rescue procedures (including the use of breathing apparatus) if the alarm sounds